// SPDX-License-Identifier: GPL-2.0-only
/*
 * Driver for I2C adapter in Rockchip RK3xxx SoC
 *
 * Max Schwarz <max.schwarz@online.de>
 * based on the patches by Rockchip Inc.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/iopoll.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/spinlock.h>
#include <linux/clk.h>
#include <linux/wait.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
#include <linux/math64.h>
#include <linux/reboot.h>
#include <linux/delay.h>

/* Register Map */
#define REG_CON 0x00      /* control register */
#define REG_CLKDIV 0x04   /* clock divisor register */
#define REG_MRXADDR 0x08  /* slave address for REGISTER_TX */
#define REG_MRXRADDR 0x0c /* slave register address for REGISTER_TX */
#define REG_MTXCNT 0x10   /* number of bytes to be transmitted */
#define REG_MRXCNT 0x14   /* number of bytes to be received */
#define REG_IEN 0x18      /* interrupt enable */
#define REG_IPD 0x1c      /* interrupt pending */
#define REG_FCNT 0x20     /* finished count */

/* Data buffer offsets */
#define TXBUFFER_BASE 0x100
#define RXBUFFER_BASE 0x200

/* REG_CON bits */
#define REG_CON_EN BIT(0)
enum {
    REG_CON_MOD_TX = 0,      /* transmit data */
    REG_CON_MOD_REGISTER_TX, /* select register and restart */
    REG_CON_MOD_RX,          /* receive data */
    REG_CON_MOD_REGISTER_RX, /* broken: transmits read addr AND writes
                              * register addr */
};
#define REG_CON_MOD(mod) ((mod) << 1)
#define REG_CON_MOD_MASK (BIT(1) | BIT(2))
#define REG_CON_START BIT(3)
#define REG_CON_STOP BIT(4)
#define REG_CON_LASTACK BIT(5) /* 1: send NACK after last received byte */
#define REG_CON_ACTACK BIT(6)  /* 1: stop if NACK is received */

#define REG_CON_TUNING_MASK GENMASK_ULL(15, 8)

#define REG_CON_SDA_CFG(cfg) ((cfg) << 8)
#define REG_CON_STA_CFG(cfg) ((cfg) << 12)
#define REG_CON_STO_CFG(cfg) ((cfg) << 14)

/* REG_MRXADDR bits */
#define REG_MRXADDR_VALID(x) BIT(24 + (x)) /* [x*8+7:x*8] of MRX[R]ADDR valid */

/* REG_IEN/REG_IPD bits */
#define REG_INT_BTF BIT(0)    /* a byte was transmitted */
#define REG_INT_BRF BIT(1)    /* a byte was received */
#define REG_INT_MBTF BIT(2)   /* master data transmit finished */
#define REG_INT_MBRF BIT(3)   /* master data receive finished */
#define REG_INT_START BIT(4)  /* START condition generated */
#define REG_INT_STOP BIT(5)   /* STOP condition generated */
#define REG_INT_NAKRCV BIT(6) /* NACK received */
#define REG_INT_ALL 0xff

/* Disable i2c all irqs */
#define IEN_ALL_DISABLE 0

/* Constants */
#define WAIT_TIMEOUT 1000             /* ms */
#define DEFAULT_SCL_RATE (100 * 1000) /* Hz */

#define RK_I2C_MSG_LEN_MAX 32
#define RK_I2C_TX_TIMES_COUNT 8
#define RK_I2C_DWORD_TO_BYTE_COUNT 4
#define RK_I2C_BYTE_TO_BIT_COUNT 8
#define RK_I2C_ADDR_MASK 0x7f
#define RK_I2C_BYTE_VALUE_MASK 0xff
#define RK_I2C_BUS_FREQ_MIN 1000
#define RK_I2C_MIN_HIGH_NS_DIV_ROUND_PARA_ONE 875
#define RK_I2C_MIN_HIGH_NS_DIV_ROUND_PARA_TWO 2
#define RK_I2C_SCL_RATE_HZ_MUL 8
#define RK_I2C_SCL_RATE_HZ_VALUE 1000000
#define RK_I2C_MAX_DIV_VALUE 0xffff
#define RK_I2C_SCL_MIN_VALUE 2
#define RK_I2C_SDA_UPDATA_CFG_TIMES 3
#define RK_I2C_S_TO_NS 1000000000
#define RK_I2C_SCL_DIV_HIGH_SHIFT_MASK 16
#define RK_I2C_MSG_LEN_MIN 4
#define RK_I2C_MSG_NUM 2
#define RK_I2C_WAIT_POLL_UDELAY_VALUE_FIVE 5
#define RK_I2C_WAIT_POLL_UDELAY_VALUE_TEN 10
#define RK_I2C_PROBE_RETRY_TIMES 3
#define RK_I2C_RESTART_PRIORITY_VALUE 128
#define RK_I2C_BIT_MASK_FOUR 4
#define RK_I2C_BIT_MASK_TEN 10
#define RK_I2C_BIT_MASK_ELEVEN 11
#define RK_I2C_BIT_MASK_TWENTY 20
#define RK_I2C_BIT_MASK_TWENTY_SIX 26
#define RK_I2C_BIT_MASK_TWENTY_SEVEN 27
#define RK_I2C_ADAPTER_NUM 2

/**
 * struct i2c_spec_values:
 * @min_hold_start_ns: min hold time (repeated) START condition
 * @min_low_ns: min LOW period of the SCL clock
 * @min_high_ns: min HIGH period of the SCL cloc
 * @min_setup_start_ns: min set-up time for a repeated START conditio
 * @max_data_hold_ns: max data hold time
 * @min_data_setup_ns: min data set-up time
 * @min_setup_stop_ns: min set-up time for STOP condition
 * @min_hold_buffer_ns: min bus free time between a STOP and
 * START condition
 */
struct i2c_spec_values {
    unsigned long min_hold_start_ns;
    unsigned long min_low_ns;
    unsigned long min_high_ns;
    unsigned long min_setup_start_ns;
    unsigned long max_data_hold_ns;
    unsigned long min_data_setup_ns;
    unsigned long min_setup_stop_ns;
    unsigned long min_hold_buffer_ns;
};

static const struct i2c_spec_values standard_mode_spec = {
    .min_hold_start_ns = 4000,
    .min_low_ns = 4700,
    .min_high_ns = 4000,
    .min_setup_start_ns = 4700,
    .max_data_hold_ns = 3450,
    .min_data_setup_ns = 250,
    .min_setup_stop_ns = 4000,
    .min_hold_buffer_ns = 4700,
};

static const struct i2c_spec_values fast_mode_spec = {
    .min_hold_start_ns = 600,
    .min_low_ns = 1300,
    .min_high_ns = 600,
    .min_setup_start_ns = 600,
    .max_data_hold_ns = 900,
    .min_data_setup_ns = 100,
    .min_setup_stop_ns = 600,
    .min_hold_buffer_ns = 1300,
};

static const struct i2c_spec_values fast_mode_plus_spec = {
    .min_hold_start_ns = 260,
    .min_low_ns = 500,
    .min_high_ns = 260,
    .min_setup_start_ns = 260,
    .max_data_hold_ns = 400,
    .min_data_setup_ns = 50,
    .min_setup_stop_ns = 260,
    .min_hold_buffer_ns = 500,
};

/**
 * struct rk3x_i2c_calced_timings:
 * @div_low: Divider output for low
 * @div_high: Divider output for high
 * @tuning: Used to adjust setup/hold data time,
 * setup/hold start time and setup stop time for
 * v1's calc_timings, the tuning should all be 0
 * for old hardware anyone using v0's calc_timings.
 */
struct rk3x_i2c_calced_timings {
    unsigned long div_low;
    unsigned long div_high;
    unsigned int tuning;
};

enum rk3x_i2c_state { STATE_IDLE, STATE_READ, STATE_WRITE, STATE_STOP };

/**
 * struct rk3x_i2c_soc_data:
 * @grf_offset: offset inside the grf regmap for setting the i2c type
 * @calc_timings: Callback function for i2c timing information calculated
 */
struct rk3x_i2c_soc_data {
    int grf_offset;
    int (*calc_timings)(unsigned long, struct i2c_timings *, struct rk3x_i2c_calced_timings *);
};

/**
 * struct rk3x_i2c - private data of the controller
 * @adap: corresponding I2C adapter
 * @dev: device for this controller
 * @soc_data: related soc data struct
 * @regs: virtual memory area
 * @clk: function clk for rk3399 or function & Bus clks for others
 * @pclk: Bus clk for rk3399
 * @clk_rate_nb: i2c clk rate change notify
 * @t: I2C known timing information
 * @lock: spinlock for the i2c bus
 * @wait: the waitqueue to wait for i2c transfer
 * @busy: the condition for the event to wait for
 * @msg: current i2c message
 * @addr: addr of i2c slave device
 * @mode: mode of i2c transfer
 * @is_last_msg: flag determines whether it is the last msg in this transfer
 * @state: state of i2c transfer
 * @processed: byte length which has been send or received
 * @error: error code for i2c transfer
 * @i2c_restart_nb: make sure the i2c transfer to be finished
 * @system_restarting: true if system is restarting
 */
struct rk3x_i2c {
    struct i2c_adapter adap;
    struct device *dev;
    const struct rk3x_i2c_soc_data *soc_data;

    /* Hardware resources */
    void __iomem *regs;
    struct clk *clk;
    struct clk *pclk;
    struct notifier_block clk_rate_nb;

    /* Settings */
    struct i2c_timings t;

    /* Synchronization & notification */
    spinlock_t lock;
    wait_queue_head_t wait;
    bool busy;

    /* Current message */
    struct i2c_msg *msg;
    u8 addr;
    unsigned int mode;
    bool is_last_msg;

    /* I2C state machine */
    enum rk3x_i2c_state state;
    unsigned int processed;
    int error;
    unsigned int suspended : 1;

    struct notifier_block i2c_restart_nb;
    bool system_restarting;
};

static void rk3x_i2c_prepare_read(struct rk3x_i2c *i2c);
static int rk3x_i2c_fill_transmit_buf(struct rk3x_i2c *i2c, bool sended);

static inline void rk3x_i2c_wake_up(struct rk3x_i2c *i2c)
{
    if (!i2c->system_restarting) {
        wake_up(&i2c->wait);
    }
}

static inline void i2c_writel(struct rk3x_i2c *i2c, u32 value, unsigned int offset)
{
    writel(value, i2c->regs + offset);
}

static inline u32 i2c_readl(struct rk3x_i2c *i2c, unsigned int offset)
{
    return readl(i2c->regs + offset);
}

/* Reset all interrupt pending bits */
static inline void rk3x_i2c_clean_ipd(struct rk3x_i2c *i2c)
{
    i2c_writel(i2c, REG_INT_ALL, REG_IPD);
}

static inline void rk3x_i2c_disable_irq(struct rk3x_i2c *i2c)
{
    i2c_writel(i2c, IEN_ALL_DISABLE, REG_IEN);
}

static inline void rk3x_i2c_disable(struct rk3x_i2c *i2c)
{
    u32 val = i2c_readl(i2c, REG_CON) & REG_CON_TUNING_MASK;

    i2c_writel(i2c, val, REG_CON);
}

/**
 * Generate a START condition, which triggers a REG_INT_START interrupt.
 */
static void rk3x_i2c_start(struct rk3x_i2c *i2c)
{
    u32 val = i2c_readl(i2c, REG_CON) & REG_CON_TUNING_MASK;
    int length = 0;

    /* enable appropriate interrupts */
    if (i2c->mode == REG_CON_MOD_TX) {
        i2c_writel(i2c, REG_INT_MBTF | REG_INT_NAKRCV, REG_IEN);
        i2c->state = STATE_WRITE;
        length = rk3x_i2c_fill_transmit_buf(i2c, false);
    } else {
        /* in any other case, we are going to be reading. */
        i2c_writel(i2c, REG_INT_MBRF | REG_INT_NAKRCV, REG_IEN);
        i2c->state = STATE_READ;
    }

    /* enable adapter with correct mode, send START condition */
    val |= REG_CON_EN | REG_CON_MOD(i2c->mode) | REG_CON_START;

    /* if we want to react to NACK, set ACTACK bit */
    if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
        val |= REG_CON_ACTACK;
    }

    i2c_writel(i2c, val, REG_CON);

    /* enable transition */
    if (i2c->mode == REG_CON_MOD_TX) {
        i2c_writel(i2c, length, REG_MTXCNT);
    } else {
        rk3x_i2c_prepare_read(i2c);
    }
}

/**
 * Generate a STOP condition, which triggers a REG_INT_STOP interrupt.
 *
 * @error: Error code to return in rk3x_i2c_xfer
 */
static void rk3x_i2c_stop(struct rk3x_i2c *i2c, int error)
{
    unsigned int ctrl;

    i2c->processed = 0;
    i2c->msg = NULL;
    i2c->error = error;

    if (i2c->is_last_msg) {
        /* Enable stop interrupt */
        i2c_writel(i2c, REG_INT_STOP, REG_IEN);

        i2c->state = STATE_STOP;

        ctrl = i2c_readl(i2c, REG_CON);
        ctrl |= REG_CON_STOP;
        ctrl &= ~REG_CON_START;
        i2c_writel(i2c, ctrl, REG_CON);
    } else {
        /* Signal rk3x_i2c_xfer to start the next message. */
        i2c->busy = false;
        i2c->state = STATE_IDLE;

        /*
         * The HW is actually not capable of REPEATED START. But we can
         * get the intended effect by resetting its internal state
         * and issuing an ordinary START.
         */
        ctrl = i2c_readl(i2c, REG_CON) & REG_CON_TUNING_MASK;
        i2c_writel(i2c, ctrl, REG_CON);

        /* signal that we are finished with the current msg */
        rk3x_i2c_wake_up(i2c);
    }
}

/**
 * Setup a read according to i2c->msg
 */
static void rk3x_i2c_prepare_read(struct rk3x_i2c *i2c)
{
    unsigned int len = i2c->msg->len - i2c->processed;
    u32 con;

    con = i2c_readl(i2c, REG_CON);

    /*
     * The hw can read up to 32 bytes at a time. If we need more than one
     * chunk, send an ACK after the last byte of the current chunk.
     */
    if (len > RK_I2C_MSG_LEN_MAX) {
        len = RK_I2C_MSG_LEN_MAX;
        con &= ~REG_CON_LASTACK;
    } else {
        con |= REG_CON_LASTACK;
    }

    /* make sure we are in plain RX mode if we read a second chunk */
    if (i2c->processed != 0) {
        con &= ~REG_CON_MOD_MASK;
        con |= REG_CON_MOD(REG_CON_MOD_RX);
        if (con & REG_CON_START) {
            con &= ~REG_CON_START;
        }
    }

    i2c_writel(i2c, con, REG_CON);
    i2c_writel(i2c, len, REG_MRXCNT);
}

/**
 * Fill the transmit buffer with data from i2c->msg
 */
static int rk3x_i2c_fill_transmit_buf(struct rk3x_i2c *i2c, bool sendend)
{
    unsigned int i, j;
    u32 cnt = 0;
    u32 val;
    u8 byte;

    for (i = 0; i < RK_I2C_TX_TIMES_COUNT; ++i) {
        val = 0;
        for (j = 0; j < RK_I2C_DWORD_TO_BYTE_COUNT; ++j) {
            if ((i2c->processed == i2c->msg->len) && (cnt != 0)) {
                break;
            }

            if (i2c->processed == 0 && cnt == 0) {
                byte = (i2c->addr & RK_I2C_ADDR_MASK) << 1;
            } else {
                byte = i2c->msg->buf[i2c->processed++];
            }

            val |= byte << (j * RK_I2C_BYTE_TO_BIT_COUNT);
            cnt++;
        }

        i2c_writel(i2c, val, TXBUFFER_BASE + RK_I2C_DWORD_TO_BYTE_COUNT * i);

        if (i2c->processed == i2c->msg->len) {
            break;
        }
    }

    if (sendend) {
        i2c_writel(i2c, cnt, REG_MTXCNT);
    }

    return cnt;
}

/* IRQ handlers for individual states */

static void rk3x_i2c_handle_write(struct rk3x_i2c *i2c, unsigned int ipd)
{
    if (!(ipd & REG_INT_MBTF)) {
        rk3x_i2c_stop(i2c, -EIO);
        dev_err(i2c->dev, "unexpected irq in WRITE: 0x%x\n", ipd);
        rk3x_i2c_clean_ipd(i2c);
        return;
    }

    /* ack interrupt */
    i2c_writel(i2c, REG_INT_MBTF, REG_IPD);

    /* are we finished? */
    if (i2c->processed == i2c->msg->len) {
        rk3x_i2c_stop(i2c, i2c->error);
    } else {
        rk3x_i2c_fill_transmit_buf(i2c, true);
    }
}

static void rk3x_i2c_handle_read(struct rk3x_i2c *i2c, unsigned int ipd)
{
    unsigned int i;
    unsigned int len = i2c->msg->len - i2c->processed;
    u32 val;
    u8 byte;

    /* we only care for MBRF here. */
    if (!(ipd & REG_INT_MBRF)) {
        return;
    }

    /* ack interrupt */
    i2c_writel(i2c, REG_INT_MBRF | REG_INT_START, REG_IPD);

    /* Can only handle a maximum of 32 bytes at a time */
    if (len > RK_I2C_MSG_LEN_MAX) {
        len = RK_I2C_MSG_LEN_MAX;
    }

    /* read the data from receive buffer */
    for (i = 0; i < len; ++i) {
        if (i % RK_I2C_DWORD_TO_BYTE_COUNT == 0) {
            val = i2c_readl(i2c, RXBUFFER_BASE + (i / RK_I2C_DWORD_TO_BYTE_COUNT) * RK_I2C_DWORD_TO_BYTE_COUNT);
        }

        byte = (val >> ((i % RK_I2C_DWORD_TO_BYTE_COUNT) * RK_I2C_BYTE_TO_BIT_COUNT)) & RK_I2C_BYTE_VALUE_MASK;
        i2c->msg->buf[i2c->processed++] = byte;
    }

    /* are we finished? */
    if (i2c->processed == i2c->msg->len) {
        rk3x_i2c_stop(i2c, i2c->error);
    } else {
        rk3x_i2c_prepare_read(i2c);
    }
}

static void rk3x_i2c_handle_stop(struct rk3x_i2c *i2c, unsigned int ipd)
{
    unsigned int con;

    if (!(ipd & REG_INT_STOP)) {
        rk3x_i2c_stop(i2c, -EIO);
        dev_err(i2c->dev, "unexpected irq in STOP: 0x%x\n", ipd);
        rk3x_i2c_clean_ipd(i2c);
        return;
    }

    /* ack interrupt */
    i2c_writel(i2c, REG_INT_STOP, REG_IPD);

    /* disable STOP bit */
    con = i2c_readl(i2c, REG_CON);
    con &= ~REG_CON_STOP;
    i2c_writel(i2c, con, REG_CON);

    i2c->busy = false;
    i2c->state = STATE_IDLE;

    /* signal rk3x_i2c_xfer that we are finished */
    rk3x_i2c_wake_up(i2c);
}

static irqreturn_t rk3x_i2c_irq(int irqno, void *dev_id)
{
    struct rk3x_i2c *i2c = dev_id;
    unsigned int ipd;
    spin_lock(&i2c->lock);
    ipd = i2c_readl(i2c, REG_IPD);
    if (i2c->state == STATE_IDLE) {
        dev_warn_ratelimited(i2c->dev, "irq in STATE_IDLE, ipd = 0x%x\n", ipd);
        rk3x_i2c_clean_ipd(i2c);
        goto out;
    }
    dev_dbg(i2c->dev, "IRQ: state %d, ipd: %x\n", i2c->state, ipd);
    /* Clean interrupt bits we don't care about */
    ipd &= ~(REG_INT_BRF | REG_INT_BTF);
    if (ipd & REG_INT_NAKRCV) {
        /*
         * We got a NACK in the last operation. Depending on whether
         * IGNORE_NAK is set, we have to stop the operation and report
         * an error.
         */
        i2c_writel(i2c, REG_INT_NAKRCV, REG_IPD);

        ipd &= ~REG_INT_NAKRCV;

        if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
            rk3x_i2c_stop(i2c, -ENXIO);
            goto out;
        }
    }
    /* is there anything left to handle? */
    if ((ipd & REG_INT_ALL) == 0) {
        goto out;
    }
    switch (i2c->state) {
        case STATE_WRITE:
            rk3x_i2c_handle_write(i2c, ipd);
            break;
        case STATE_READ:
            rk3x_i2c_handle_read(i2c, ipd);
            break;
        case STATE_STOP:
            rk3x_i2c_handle_stop(i2c, ipd);
            break;
        case STATE_IDLE:
            break;
    }

out:
    spin_unlock(&i2c->lock);
    return IRQ_HANDLED;
}

/**
 * Get timing values of I2C specification
 *
 * @speed: Desired SCL frequency
 *
 * Returns: Matched i2c spec values.
 */
static const struct i2c_spec_values *rk3x_i2c_get_spec(unsigned int speed)
{
    if (speed <= I2C_MAX_STANDARD_MODE_FREQ) {
        return &standard_mode_spec;
    } else if (speed <= I2C_MAX_FAST_MODE_FREQ) {
        return &fast_mode_spec;
    } else {
        return &fast_mode_plus_spec;
    }
}

/**
 * Calculate divider values for desired SCL frequency
 *
 * @clk_rate: I2C input clock rate
 * @t: Known I2C timing information
 * @t_calc: Caculated rk3x private timings that would be written into regs
 *
 * Returns: 0 on success, -EINVAL if the goal SCL rate is too slow. In that case
 * a best-effort divider value is returned in divs. If the target rate is
 * too high, we silently use the highest possible rate.
 */
static int rk3x_i2c_v0_calc_timings(unsigned long clk_rate, struct i2c_timings *t,
                                    struct rk3x_i2c_calced_timings *t_calc)
{
    unsigned long min_low_ns, min_high_ns;
    unsigned long max_low_ns, min_total_ns;

    unsigned long clk_rate_khz, scl_rate_khz;

    unsigned long min_low_div, min_high_div;
    unsigned long max_low_div;

    unsigned long min_div_for_hold, min_total_div;
    unsigned long extra_div, extra_low_div, ideal_low_div;

    unsigned long data_hold_buffer_ns = 50;
    const struct i2c_spec_values *spec;
    int ret = 0;

    /* Only support standard-mode and fast-mode */
    if (WARN_ON(t->bus_freq_hz > I2C_MAX_FAST_MODE_FREQ)) {
        t->bus_freq_hz = I2C_MAX_FAST_MODE_FREQ;
    }

    /* prevent scl_rate_khz from becoming 0 */
    if (WARN_ON(t->bus_freq_hz < RK_I2C_BUS_FREQ_MIN)) {
        t->bus_freq_hz = RK_I2C_BUS_FREQ_MIN;
    }

    /*
     * min_low_ns:  The minimum number of ns we need to hold low to
     *        meet I2C specification, should include fall time.
     * min_high_ns: The minimum number of ns we need to hold high to
     *        meet I2C specification, should include rise time.
     * max_low_ns:  The maximum number of ns we can hold low to meet
     *        I2C specification.
     *
     * Note: max_low_ns should be (maximum data hold time * 2 - buffer)
     *     This is because the i2c host on Rockchip holds the data line
     *     for half the low time.
     */
    spec = rk3x_i2c_get_spec(t->bus_freq_hz);
    min_high_ns = t->scl_rise_ns + spec->min_high_ns;

    /*
     * Timings for repeated start:
     * - controller appears to drop SDA at .875x (7/8) programmed clk high.
     * - controller appears to keep SCL high for 2x programmed clk high.
     *
     * We need to account for those rules in picking our "high" time so
     * we meet tSU;STA and tHD;STA times.
     */
    min_high_ns = max(min_high_ns, DIV_ROUND_UP((t->scl_rise_ns + spec->min_setup_start_ns) * RK_I2C_BUS_FREQ_MIN,
                                                RK_I2C_MIN_HIGH_NS_DIV_ROUND_PARA_ONE));
    min_high_ns =
        max(min_high_ns, DIV_ROUND_UP((t->scl_rise_ns + spec->min_setup_start_ns + t->sda_fall_ns + spec->min_high_ns),
                                      RK_I2C_MIN_HIGH_NS_DIV_ROUND_PARA_TWO));

    min_low_ns = t->scl_fall_ns + spec->min_low_ns;
    max_low_ns = spec->max_data_hold_ns * RK_I2C_MIN_HIGH_NS_DIV_ROUND_PARA_TWO - data_hold_buffer_ns;
    min_total_ns = min_low_ns + min_high_ns;

    /* Adjust to avoid overflow */
    clk_rate_khz = DIV_ROUND_UP(clk_rate, RK_I2C_BUS_FREQ_MIN);
    scl_rate_khz = t->bus_freq_hz / RK_I2C_BUS_FREQ_MIN;

    /*
     * We need the total div to be >= this number
     * so we don't clock too fast.
     */
    min_total_div = DIV_ROUND_UP(clk_rate_khz, scl_rate_khz * RK_I2C_SCL_RATE_HZ_MUL);

    /* These are the min dividers needed for min hold times. */
    min_low_div = DIV_ROUND_UP(clk_rate_khz * min_low_ns, RK_I2C_SCL_RATE_HZ_MUL * RK_I2C_SCL_RATE_HZ_VALUE);
    min_high_div = DIV_ROUND_UP(clk_rate_khz * min_high_ns, RK_I2C_SCL_RATE_HZ_MUL * RK_I2C_SCL_RATE_HZ_VALUE);
    min_div_for_hold = (min_low_div + min_high_div);

    /*
     * This is the maximum divider so we don't go over the maximum.
     * We don't round up here (we round down) since this is a maximum.
     */
    max_low_div = clk_rate_khz * max_low_ns / (RK_I2C_SCL_RATE_HZ_MUL * RK_I2C_SCL_RATE_HZ_VALUE);

    if (min_low_div > max_low_div) {
        WARN_ONCE(true, "Conflicting, min_low_div %lu, max_low_div %lu\n", min_low_div, max_low_div);
        max_low_div = min_low_div;
    }

    if (min_div_for_hold > min_total_div) {
        /*
         * Time needed to meet hold requirements is important.
         * Just use that.
         */
        t_calc->div_low = min_low_div;
        t_calc->div_high = min_high_div;
    } else {
        /*
         * We've got to distribute some time among the low and high
         * so we don't run too fast.
         */
        extra_div = min_total_div - min_div_for_hold;
        /*
         * We'll try to split things up perfectly evenly,
         * biasing slightly towards having a higher div
         * for low (spend more time low).
         */
        ideal_low_div = DIV_ROUND_UP(clk_rate_khz * min_low_ns, scl_rate_khz * RK_I2C_SCL_RATE_HZ_MUL * min_total_ns);
        /* Don't allow it to go over the maximum */
        if (ideal_low_div > max_low_div) {
            ideal_low_div = max_low_div;
        }
        /*
         * Handle when the ideal low div is going to take up
         * more than we have.
         */
        if (ideal_low_div > min_low_div + extra_div) {
            ideal_low_div = min_low_div + extra_div;
        }
        /* Give low the "ideal" and give high whatever extra is left */
        extra_low_div = ideal_low_div - min_low_div;
        t_calc->div_low = ideal_low_div;
        t_calc->div_high = min_high_div + (extra_div - extra_low_div);
    }

    /*
     * Adjust to the fact that the hardware has an implicit "+1".
     * NOTE: Above calculations always produce div_low > 0 and div_high > 0.
     */
    t_calc->div_low--;
    t_calc->div_high--;

    /* Give the tuning value 0, that would not update con register */
    t_calc->tuning = 0;
    /* Maximum divider supported by hw is 0xffff */
    if (t_calc->div_low > RK_I2C_MAX_DIV_VALUE) {
        t_calc->div_low = RK_I2C_MAX_DIV_VALUE;
        ret = -EINVAL;
    }

    if (t_calc->div_high > RK_I2C_MAX_DIV_VALUE) {
        t_calc->div_high = RK_I2C_MAX_DIV_VALUE;
        ret = -EINVAL;
    }

    return ret;
}

/**
 * Calculate timing values for desired SCL frequency
 *
 * @clk_rate: I2C input clock rate
 * @t: Known I2C timing information
 * @t_calc: Caculated rk3x private timings that would be written into regs
 *
 * Returns: 0 on success, -EINVAL if the goal SCL rate is too slow. In that case
 * a best-effort divider value is returned in divs. If the target rate is
 * too high, we silently use the highest possible rate.
 * The following formulas are v1's method to calculate timings.
 *
 * l = divl + 1;
 * h = divh + 1;
 * s = sda_update_config + 1;
 * u = start_setup_config + 1;
 * p = stop_setup_config + 1;
 * T = Tclk_i2c;
 *
 * tHigh = 8 * h * T;
 * tLow = 8 * l * T;
 *
 * tHD;sda = (l * s + 1) * T;
 * tSU;sda = [(8 - s) * l + 1] * T;
 * tI2C = 8 * (l + h) * T;
 *
 * tSU;sta = (8h * u + 1) * T;
 * tHD;sta = [8h * (u + 1) - 1] * T;
 * tSU;sto = (8h * p + 1) * T;
 */
static int rk3x_i2c_v1_calc_timings(unsigned long clk_rate, struct i2c_timings *t,
                                    struct rk3x_i2c_calced_timings *t_calc)
{
    unsigned long min_low_ns, min_high_ns;
    unsigned long min_setup_start_ns, min_setup_data_ns;
    unsigned long min_setup_stop_ns, max_hold_data_ns;

    unsigned long clk_rate_khz, scl_rate_khz;

    unsigned long min_low_div, min_high_div;

    unsigned long min_div_for_hold, min_total_div;
    unsigned long extra_div, extra_low_div;
    unsigned long sda_update_cfg, stp_sta_cfg, stp_sto_cfg;

    const struct i2c_spec_values *spec;
    int ret = 0;

    /* Support standard-mode, fast-mode and fast-mode plus */
    if (WARN_ON(t->bus_freq_hz > I2C_MAX_FAST_MODE_PLUS_FREQ)) {
        t->bus_freq_hz = I2C_MAX_FAST_MODE_PLUS_FREQ;
    }

    /* prevent scl_rate_khz from becoming 0 */
    if (WARN_ON(t->bus_freq_hz < RK_I2C_BUS_FREQ_MIN)) {
        t->bus_freq_hz = RK_I2C_BUS_FREQ_MIN;
    }

    /*
     * min_low_ns: The minimum number of ns we need to hold low to
     *           meet I2C specification, should include fall time.
     * min_high_ns: The minimum number of ns we need to hold high to
     *            meet I2C specification, should include rise time.
     */
    spec = rk3x_i2c_get_spec(t->bus_freq_hz);

    /* calculate min-divh and min-divl */
    clk_rate_khz = DIV_ROUND_UP(clk_rate, RK_I2C_BUS_FREQ_MIN);
    scl_rate_khz = t->bus_freq_hz / RK_I2C_BUS_FREQ_MIN;
    min_total_div = DIV_ROUND_UP(clk_rate_khz, scl_rate_khz * RK_I2C_SCL_RATE_HZ_MUL);

    min_high_ns = t->scl_rise_ns + spec->min_high_ns;
    min_high_div = DIV_ROUND_UP(clk_rate_khz * min_high_ns, RK_I2C_SCL_RATE_HZ_MUL * RK_I2C_SCL_RATE_HZ_VALUE);

    min_low_ns = t->scl_fall_ns + spec->min_low_ns;
    min_low_div = DIV_ROUND_UP(clk_rate_khz * min_low_ns, RK_I2C_SCL_RATE_HZ_MUL * RK_I2C_SCL_RATE_HZ_VALUE);

    /*
     * Final divh and divl must be greater than 0, otherwise the
     * hardware would not output the i2c clk.
     */
    min_high_div = (min_high_div < 1) ? RK_I2C_SCL_MIN_VALUE : min_high_div;
    min_low_div = (min_low_div < 1) ? RK_I2C_SCL_MIN_VALUE : min_low_div;

    /* These are the min dividers needed for min hold times. */
    min_div_for_hold = (min_low_div + min_high_div);

    /*
     * This is the maximum divider so we don't go over the maximum.
     * We don't round up here (we round down) since this is a maximum.
     */
    if (min_div_for_hold >= min_total_div) {
        /*
         * Time needed to meet hold requirements is important.
         * Just use that.
         */
        t_calc->div_low = min_low_div;
        t_calc->div_high = min_high_div;
    } else {
        /*
         * We've got to distribute some time among the low and high
         * so we don't run too fast.
         * We'll try to split things up by the scale of min_low_div and
         * min_high_div, biasing slightly towards having a higher div
         * for low (spend more time low).
         */
        extra_div = min_total_div - min_div_for_hold;
        extra_low_div = DIV_ROUND_UP(min_low_div * extra_div, min_div_for_hold);

        t_calc->div_low = min_low_div + extra_low_div;
        t_calc->div_high = min_high_div + (extra_div - extra_low_div);
    }

    /*
     * calculate sda data hold count by the rules, data_upd_st:3
     * is a appropriate value to reduce calculated times.
     */
    for (sda_update_cfg = RK_I2C_SDA_UPDATA_CFG_TIMES; sda_update_cfg > 0; sda_update_cfg--) {
        max_hold_data_ns =
            DIV_ROUND_UP((sda_update_cfg * (t_calc->div_low) + 1) * RK_I2C_SCL_RATE_HZ_VALUE, clk_rate_khz);
        min_setup_data_ns =
            DIV_ROUND_UP(((RK_I2C_SCL_RATE_HZ_MUL - sda_update_cfg) * (t_calc->div_low) + 1) * RK_I2C_SCL_RATE_HZ_VALUE,
                         clk_rate_khz);
        if ((max_hold_data_ns < spec->max_data_hold_ns) && (min_setup_data_ns > spec->min_data_setup_ns)) {
            break;
        }
    }

    /* calculate setup start config */
    min_setup_start_ns = t->scl_rise_ns + spec->min_setup_start_ns;
    stp_sta_cfg = DIV_ROUND_UP(clk_rate_khz * min_setup_start_ns - RK_I2C_SCL_RATE_HZ_VALUE,
                               RK_I2C_SCL_RATE_HZ_MUL * RK_I2C_SCL_RATE_HZ_VALUE * (t_calc->div_high));

    /* calculate setup stop config */
    min_setup_stop_ns = t->scl_rise_ns + spec->min_setup_stop_ns;
    stp_sto_cfg = DIV_ROUND_UP(clk_rate_khz * min_setup_stop_ns - RK_I2C_SCL_RATE_HZ_VALUE,
                               RK_I2C_SCL_RATE_HZ_MUL * RK_I2C_SCL_RATE_HZ_VALUE * (t_calc->div_high));

    t_calc->tuning =
        REG_CON_SDA_CFG(--sda_update_cfg) | REG_CON_STA_CFG(--stp_sta_cfg) | REG_CON_STO_CFG(--stp_sto_cfg);

    t_calc->div_low--;
    t_calc->div_high--;

    /* Maximum divider supported by hw is 0xffff */
    if (t_calc->div_low > RK_I2C_MAX_DIV_VALUE) {
        t_calc->div_low = RK_I2C_MAX_DIV_VALUE;
        ret = -EINVAL;
    }

    if (t_calc->div_high > RK_I2C_MAX_DIV_VALUE) {
        t_calc->div_high = RK_I2C_MAX_DIV_VALUE;
        ret = -EINVAL;
    }

    return ret;
}

static void rk3x_i2c_adapt_div(struct rk3x_i2c *i2c, unsigned long clk_rate)
{
    struct i2c_timings *t = &i2c->t;
    struct rk3x_i2c_calced_timings calc;
    u64 t_low_ns, t_high_ns;
    unsigned long flags;
    u32 val;
    int ret;

    ret = i2c->soc_data->calc_timings(clk_rate, t, &calc);
    WARN_ONCE(ret != 0, "Could not reach SCL freq %u", t->bus_freq_hz);

    clk_enable(i2c->pclk);

    spin_lock_irqsave(&i2c->lock, flags);
    val = i2c_readl(i2c, REG_CON);
    val &= ~REG_CON_TUNING_MASK;
    val |= calc.tuning;
    i2c_writel(i2c, val, REG_CON);
    i2c_writel(i2c, (calc.div_high << RK_I2C_SCL_DIV_HIGH_SHIFT_MASK) | (calc.div_low & RK_I2C_MAX_DIV_VALUE),
               REG_CLKDIV);
    spin_unlock_irqrestore(&i2c->lock, flags);

    clk_disable(i2c->pclk);

    t_low_ns = div_u64(((u64)calc.div_low + 1) * RK_I2C_SCL_RATE_HZ_MUL * RK_I2C_S_TO_NS, clk_rate);
    t_high_ns = div_u64(((u64)calc.div_high + 1) * RK_I2C_SCL_RATE_HZ_MUL * RK_I2C_S_TO_NS, clk_rate);
}

/**
 * rk3x_i2c_clk_notifier_cb - Clock rate change callback
 * @nb:        Pointer to notifier block
 * @event:    Notification reason
 * @data:    Pointer to notification data object
 *
 * The callback checks whether a valid bus frequency can be generated after the
 * change. If so, the change is acknowledged, otherwise the change is aborted.
 * New dividers are written to the HW in the pre- or post change notification
 * depending on the scaling direction.
 *
 * Code adapted from i2c-cadence.c.
 *
 * Return:    NOTIFY_STOP if the rate change should be aborted, NOTIFY_OK
 *        to acknowledge the change, NOTIFY_DONE if the notification is
 *        considered irrelevant.
 */
static int rk3x_i2c_clk_notifier_cb(struct notifier_block *nb, unsigned long event, void *data)
{
    struct clk_notifier_data *ndata = data;
    struct rk3x_i2c *i2c = container_of(nb, struct rk3x_i2c, clk_rate_nb);
    struct rk3x_i2c_calced_timings calc;

    switch (event) {
        case PRE_RATE_CHANGE:
            /*
             * Try the calculation (but don't store the result) ahead of
             * time to see if we need to block the clock change.  Timings
             * shouldn't actually take effect until rk3x_i2c_adapt_div().
             */
            if (i2c->soc_data->calc_timings(ndata->new_rate, &i2c->t, &calc) != 0) {
                return NOTIFY_STOP;
            }

            /* scale up */
            if (ndata->new_rate > ndata->old_rate) {
                rk3x_i2c_adapt_div(i2c, ndata->new_rate);
            }

            return NOTIFY_OK;
        case POST_RATE_CHANGE:
            /* scale down */
            if (ndata->new_rate < ndata->old_rate) {
                rk3x_i2c_adapt_div(i2c, ndata->new_rate);
            }
            return NOTIFY_OK;
        case ABORT_RATE_CHANGE:
            /* scale up */
            if (ndata->new_rate > ndata->old_rate) {
                rk3x_i2c_adapt_div(i2c, ndata->old_rate);
            }
            return NOTIFY_OK;
        default:
            return NOTIFY_DONE;
    }
}

/**
 * Setup I2C registers for an I2C operation specified by msgs, num.
 *
 * Must be called with i2c->lock held.
 *
 * @msgs: I2C msgs to process
 * @num: Number of msgs
 *
 * returns: Number of I2C msgs processed or negative in case of error
 */
static int rk3x_i2c_setup(struct rk3x_i2c *i2c, struct i2c_msg *msgs, int num)
{
    u32 addr = (msgs[0].addr & RK_I2C_ADDR_MASK) << 1;
    int ret = 0;

    /*
     * The I2C adapter can issue a small (len < 4) write packet before
     * reading. This speeds up SMBus-style register reads.
     * The MRXADDR/MRXRADDR hold the slave address and the slave register
     * address in this case.
     */

    if (num >= RK_I2C_MSG_NUM && msgs[0].len < RK_I2C_MSG_LEN_MIN && !(msgs[0].flags & I2C_M_RD) &&
        (msgs[1].flags & I2C_M_RD)) {
        u32 reg_addr = 0;
        int i;

        dev_dbg(i2c->dev, "Combined write/read from addr 0x%x\n", addr >> 1);

        /* Fill MRXRADDR with the register address(es) */
        for (i = 0; i < msgs[0].len; ++i) {
            reg_addr |= msgs[0].buf[i] << (i * RK_I2C_BYTE_TO_BIT_COUNT);
            reg_addr |= REG_MRXADDR_VALID(i);
        }

        /* msgs[0] is handled by hw. */
        i2c->msg = &msgs[1];

        i2c->mode = REG_CON_MOD_REGISTER_TX;

        i2c_writel(i2c, addr | REG_MRXADDR_VALID(0), REG_MRXADDR);
        i2c_writel(i2c, reg_addr, REG_MRXRADDR);

        ret = 0x2;
    } else {
        /*
         * We'll have to do it the boring way and process the msgs
         * one-by-one.
         */

        if (msgs[0].flags & I2C_M_RD) {
            addr |= 1; /* set read bit */

            /*
             * We have to transmit the slave addr first. Use
             * MOD_REGISTER_TX for that purpose.
             */
            i2c->mode = REG_CON_MOD_REGISTER_TX;
            i2c_writel(i2c, addr | REG_MRXADDR_VALID(0), REG_MRXADDR);
            i2c_writel(i2c, 0, REG_MRXRADDR);
        } else {
            i2c->mode = REG_CON_MOD_TX;
        }

        i2c->msg = &msgs[0];

        ret = 1;
    }

    i2c->addr = msgs[0].addr;
    i2c->busy = true;
    i2c->processed = 0;
    i2c->error = 0;

    rk3x_i2c_clean_ipd(i2c);

    return ret;
}

static int rk3x_i2c_wait_xfer_poll(struct rk3x_i2c *i2c)
{
    ktime_t timeout = ktime_add_ms(ktime_get(), WAIT_TIMEOUT);

    while (READ_ONCE(i2c->busy) && ktime_compare(ktime_get(), timeout) < 0) {
        udelay(RK_I2C_WAIT_POLL_UDELAY_VALUE_FIVE);
        rk3x_i2c_irq(0, i2c);
    }

    return !i2c->busy;
}

static int rk3x_i2c_xfer_common(struct i2c_adapter *adap, struct i2c_msg *msgs, int num, bool polling)
{
    struct rk3x_i2c *i2c = (struct rk3x_i2c *)adap->algo_data;
    unsigned long timeout, flags;
    u32 val;
    int ret = 0;
    int i;
    if (i2c->suspended) {
        return -EACCES;
    }
    spin_lock_irqsave(&i2c->lock, flags);
    clk_enable(i2c->clk);
    clk_enable(i2c->pclk);
    i2c->is_last_msg = false;
    /*
     * Process msgs. We can handle more than one message at once (see
     * rk3x_i2c_setup()).
     */
    for (i = 0; i < num; i += ret) {
        ret = rk3x_i2c_setup(i2c, msgs + i, num - i);
        if (ret < 0) {
            dev_err(i2c->dev, "rk3x_i2c_setup() failed\n");
            break;
        }
        if (i + ret >= num) {
            i2c->is_last_msg = true;
        }
        rk3x_i2c_start(i2c);
        spin_unlock_irqrestore(&i2c->lock, flags);
        if (!polling) {
            timeout = wait_event_timeout(i2c->wait, !i2c->busy, msecs_to_jiffies(WAIT_TIMEOUT));
        } else {
            timeout = rk3x_i2c_wait_xfer_poll(i2c);
        }
        spin_lock_irqsave(&i2c->lock, flags);
        if (timeout == 0) {
            dev_err(i2c->dev, "timeout, ipd: 0x%02x, state: %d\n", i2c_readl(i2c, REG_IPD), i2c->state);
            /* Force a STOP condition without interrupt */
            rk3x_i2c_disable_irq(i2c);
            val = i2c_readl(i2c, REG_CON) & REG_CON_TUNING_MASK;
            val |= REG_CON_EN | REG_CON_STOP;
            i2c_writel(i2c, val, REG_CON);
            i2c->state = STATE_IDLE;
            ret = -ETIMEDOUT;
            break;
        }
        if (i2c->error) {
            ret = i2c->error;
            break;
        }
    }

    rk3x_i2c_disable_irq(i2c);
    rk3x_i2c_disable(i2c);

    clk_disable(i2c->pclk);
    clk_disable(i2c->clk);

    spin_unlock_irqrestore(&i2c->lock, flags);

    return ret < 0 ? ret : num;
}

static int rk3x_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
    return rk3x_i2c_xfer_common(adap, msgs, num, false);
}

static int rk3x_i2c_xfer_polling(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
    return rk3x_i2c_xfer_common(adap, msgs, num, true);
}

static int rk3x_i2c_restart_notify(struct notifier_block *this, unsigned long mode, void *cmd)
{
    struct rk3x_i2c *i2c = container_of(this, struct rk3x_i2c, i2c_restart_nb);
    int tmo = WAIT_TIMEOUT * USEC_PER_MSEC;
    u32 val;

    if (i2c->state != STATE_IDLE) {
        i2c->system_restarting = true;
        /* complete the unfinished job */
        while (tmo-- && i2c->busy) {
            udelay(1);
            rk3x_i2c_irq(0, i2c);
        }
    }

    if (tmo <= 0) {
        dev_err(i2c->dev, "restart timeout, ipd: 0x%02x, state: %d\n", i2c_readl(i2c, REG_IPD), i2c->state);

        /* Force a STOP condition without interrupt */
        i2c_writel(i2c, 0, REG_IEN);
        val = i2c_readl(i2c, REG_CON) & REG_CON_TUNING_MASK;
        val |= REG_CON_EN | REG_CON_STOP;
        i2c_writel(i2c, val, REG_CON);

        udelay(RK_I2C_WAIT_POLL_UDELAY_VALUE_TEN);
        i2c->state = STATE_IDLE;
    }

    return NOTIFY_DONE;
}

static __maybe_unused int rk3x_i2c_suspend_noirq(struct device *dev)
{
    struct rk3x_i2c *i2c = dev_get_drvdata(dev);

    /*
     * Below code is needed only to ensure that there are no
     * activities on I2C bus. if at this moment any driver
     * is trying to use I2C bus - this may cause i2c timeout.
     *
     * So forbid access to I2C device using i2c->suspended flag.
     */
    i2c_lock_bus(&i2c->adap, I2C_LOCK_ROOT_ADAPTER);
    i2c->suspended = 1;
    i2c_unlock_bus(&i2c->adap, I2C_LOCK_ROOT_ADAPTER);

    return 0;
}

static __maybe_unused int rk3x_i2c_resume_noirq(struct device *dev)
{
    struct rk3x_i2c *i2c = dev_get_drvdata(dev);

    rk3x_i2c_adapt_div(i2c, clk_get_rate(i2c->clk));

    /* Allow access to I2C bus */
    i2c_lock_bus(&i2c->adap, I2C_LOCK_ROOT_ADAPTER);
    i2c->suspended = 0;
    i2c_unlock_bus(&i2c->adap, I2C_LOCK_ROOT_ADAPTER);

    return 0;
}

static u32 rk3x_i2c_func(struct i2c_adapter *adap)
{
    return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
}

static const struct i2c_algorithm rk3x_i2c_algorithm = {
    .master_xfer = rk3x_i2c_xfer,
    .master_xfer_atomic = rk3x_i2c_xfer_polling,
    .functionality = rk3x_i2c_func,
};

static const struct rk3x_i2c_soc_data rv1108_soc_data = {
    .grf_offset = 0x408,
    .calc_timings = rk3x_i2c_v1_calc_timings,
};

static const struct rk3x_i2c_soc_data rv1126_soc_data = {
    .grf_offset = 0x118,
    .calc_timings = rk3x_i2c_v1_calc_timings,
};

static const struct rk3x_i2c_soc_data rk3066_soc_data = {
    .grf_offset = 0x154,
    .calc_timings = rk3x_i2c_v0_calc_timings,
};

static const struct rk3x_i2c_soc_data rk3188_soc_data = {
    .grf_offset = 0x0a4,
    .calc_timings = rk3x_i2c_v0_calc_timings,
};

static const struct rk3x_i2c_soc_data rk3228_soc_data = {
    .grf_offset = -1,
    .calc_timings = rk3x_i2c_v0_calc_timings,
};

static const struct rk3x_i2c_soc_data rk3288_soc_data = {
    .grf_offset = -1,
    .calc_timings = rk3x_i2c_v0_calc_timings,
};

static const struct rk3x_i2c_soc_data rk3399_soc_data = {
    .grf_offset = -1,
    .calc_timings = rk3x_i2c_v1_calc_timings,
};

static const struct of_device_id rk3x_i2c_match[] = {
    {.compatible = "rockchip,rv1108-i2c", .data = &rv1108_soc_data},
    {.compatible = "rockchip,rv1126-i2c", .data = &rv1126_soc_data},
    {.compatible = "rockchip,rk3066-i2c", .data = &rk3066_soc_data},
    {.compatible = "rockchip,rk3188-i2c", .data = &rk3188_soc_data},
    {.compatible = "rockchip,rk3228-i2c", .data = &rk3228_soc_data},
    {.compatible = "rockchip,rk3288-i2c", .data = &rk3288_soc_data},
    {.compatible = "rockchip,rk3399-i2c", .data = &rk3399_soc_data},
    {},
};
MODULE_DEVICE_TABLE(of, rk3x_i2c_match);

static int rk3x_i2c_probe(struct platform_device *pdev)
{
    struct device_node *np = pdev->dev.of_node;
    const struct of_device_id *match;
    struct rk3x_i2c *i2c;
    int ret = 0;
    u32 value;
    int irq;
    unsigned long clk_rate;

    i2c = devm_kzalloc(&pdev->dev, sizeof(struct rk3x_i2c), GFP_KERNEL);
    if (!i2c) {
        return -ENOMEM;
    }

    match = of_match_node(rk3x_i2c_match, np);
    i2c->soc_data = match->data;

    /* use common interface to get I2C timing properties */
    i2c_parse_fw_timings(&pdev->dev, &i2c->t, true);

    strlcpy(i2c->adap.name, "rk3x-i2c", sizeof(i2c->adap.name));
    i2c->adap.owner = THIS_MODULE;
    i2c->adap.algo = &rk3x_i2c_algorithm;
    i2c->adap.retries = RK_I2C_PROBE_RETRY_TIMES;
    i2c->adap.dev.of_node = np;
    i2c->adap.algo_data = i2c;
    i2c->adap.dev.parent = &pdev->dev;

    i2c->dev = &pdev->dev;

    spin_lock_init(&i2c->lock);
    init_waitqueue_head(&i2c->wait);

    i2c->i2c_restart_nb.notifier_call = rk3x_i2c_restart_notify;
    i2c->i2c_restart_nb.priority = RK_I2C_RESTART_PRIORITY_VALUE;
    ret = register_pre_restart_handler(&i2c->i2c_restart_nb);
    if (ret) {
        dev_err(&pdev->dev, "failed to setup i2c restart handler.\n");
        return ret;
    }

    i2c->regs = devm_platform_ioremap_resource(pdev, 0);
    if (IS_ERR(i2c->regs)) {
        return PTR_ERR(i2c->regs);
    }

    /*
     * Switch to new interface if the SoC also offers the old one.
     * The control bit is located in the GRF register space.
     */
    if (i2c->soc_data->grf_offset >= 0) {
        struct regmap *grf;

        grf = syscon_regmap_lookup_by_phandle(np, "rockchip,grf");
        if (!IS_ERR(grf)) {
            int bus_nr;

            /* Try to set the I2C adapter number from dt */
            bus_nr = of_alias_get_id(np, "i2c");
            if (bus_nr < 0) {
                dev_err(&pdev->dev, "rk3x-i2c needs i2cX alias");
                return -EINVAL;
            }

            if (i2c->soc_data == &rv1108_soc_data && bus_nr == RK_I2C_ADAPTER_NUM) {
                /* rv1108 i2c2 set grf offset-0x408, bit-10 */
                value = BIT(RK_I2C_BIT_MASK_TWENTY_SIX) | BIT(RK_I2C_BIT_MASK_TEN);
            } else if (i2c->soc_data == &rv1126_soc_data && bus_nr == RK_I2C_ADAPTER_NUM) {
                /* rv1126 i2c2 set pmugrf offset-0x118, bit-4 */
                value = BIT(RK_I2C_BIT_MASK_TWENTY) | BIT(RK_I2C_BIT_MASK_FOUR);
            } else {
                /* rk3xxx 27+i: write mask, 11+i: value */
                value = BIT(RK_I2C_BIT_MASK_TWENTY_SEVEN + bus_nr) | BIT(RK_I2C_BIT_MASK_ELEVEN + bus_nr);
            }

            ret = regmap_write(grf, i2c->soc_data->grf_offset, value);
            if (ret != 0) {
                dev_err(i2c->dev, "Could not write to GRF: %d\n", ret);
                return ret;
            }
        }
    }

    /* IRQ setup */
    irq = platform_get_irq(pdev, 0);
    if (irq < 0) {
        return irq;
    }

    ret = devm_request_irq(&pdev->dev, irq, rk3x_i2c_irq, 0, dev_name(&pdev->dev), i2c);
    if (ret < 0) {
        dev_err(&pdev->dev, "cannot request IRQ\n");
        return ret;
    }

    platform_set_drvdata(pdev, i2c);

    if (i2c->soc_data->calc_timings == rk3x_i2c_v0_calc_timings) {
        /* Only one clock to use for bus clock and peripheral clock */
        i2c->clk = devm_clk_get(&pdev->dev, NULL);
        i2c->pclk = i2c->clk;
    } else {
        i2c->clk = devm_clk_get(&pdev->dev, "i2c");
        i2c->pclk = devm_clk_get(&pdev->dev, "pclk");
    }

    if (IS_ERR(i2c->clk)) {
        return dev_err_probe(&pdev->dev, PTR_ERR(i2c->clk), "Can't get bus clk\n");
    }

    if (IS_ERR(i2c->pclk)) {
        return dev_err_probe(&pdev->dev, PTR_ERR(i2c->pclk), "Can't get periph clk\n");
    }

    ret = clk_prepare(i2c->clk);
    if (ret < 0) {
        dev_err(&pdev->dev, "Can't prepare bus clk: %d\n", ret);
        return ret;
    }
    ret = clk_prepare(i2c->pclk);
    if (ret < 0) {
        dev_err(&pdev->dev, "Can't prepare periph clock: %d\n", ret);
        goto err_clk;
    }

    i2c->clk_rate_nb.notifier_call = rk3x_i2c_clk_notifier_cb;
    ret = clk_notifier_register(i2c->clk, &i2c->clk_rate_nb);
    if (ret != 0) {
        dev_err(&pdev->dev, "Unable to register clock notifier\n");
        goto err_pclk;
    }

    clk_rate = clk_get_rate(i2c->clk);
    rk3x_i2c_adapt_div(i2c, clk_rate);

    ret = i2c_add_adapter(&i2c->adap);
    if (ret < 0) {
        goto err_clk_notifier;
    }

    return 0;

err_clk_notifier:
    clk_notifier_unregister(i2c->clk, &i2c->clk_rate_nb);
err_pclk:
    clk_unprepare(i2c->pclk);
err_clk:
    clk_unprepare(i2c->clk);
    return ret;
}

static int rk3x_i2c_remove(struct platform_device *pdev)
{
    struct rk3x_i2c *i2c = platform_get_drvdata(pdev);

    i2c_del_adapter(&i2c->adap);

    clk_notifier_unregister(i2c->clk, &i2c->clk_rate_nb);
    unregister_pre_restart_handler(&i2c->i2c_restart_nb);
    clk_unprepare(i2c->pclk);
    clk_unprepare(i2c->clk);

    return 0;
}

static const struct dev_pm_ops rk3x_i2c_pm_ops = {
    SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(rk3x_i2c_suspend_noirq, rk3x_i2c_resume_noirq)};

static struct platform_driver rk3x_i2c_driver = {
    .probe = rk3x_i2c_probe,
    .remove = rk3x_i2c_remove,
    .driver =
        {
            .name = "rk3x-i2c",
            .of_match_table = rk3x_i2c_match,
            .pm = &rk3x_i2c_pm_ops,
        },
};

#ifdef CONFIG_ROCKCHIP_THUNDER_BOOT
static int __init rk3x_i2c_driver_init(void)
{
    return platform_driver_register(&rk3x_i2c_driver);
}
subsys_initcall_sync(rk3x_i2c_driver_init);

static void __exit rk3x_i2c_driver_exit(void)
{
    platform_driver_unregister(&rk3x_i2c_driver);
}
module_exit(rk3x_i2c_driver_exit);
#else
module_platform_driver(rk3x_i2c_driver);
#endif

MODULE_DESCRIPTION("Rockchip RK3xxx I2C Bus driver");
MODULE_AUTHOR("Max Schwarz <max.schwarz@online.de>");
MODULE_LICENSE("GPL v2");
